Clinical characteristics and management of Turner patients with a small supernumerary marker chromosome.

Objective: To summarize the clinical characteristics of Turner syndrome (TS) with a small supernumerary marker chromosome (sSMC) and discuss the clinical significance and management of TS patients with sSMC.

Methods: A retrospective analysis was conducted on the clinical data of 244 patients with disorders of sexual development admitted to Peking Union Medical College Hospital from February 1984 to July 2020.

Results: Among the 244 patients with a disorder of sexual development, 69 cases of TS were identified in which 13 patients had sSMC. Their ages ranged from 3 to 28 years old with an average of 14.31 ± 6.40 years. All 13 sSMC-positive patients had typical clinical manifestations of TS except ambiguous genitalia in four cases. SRY gene testing was performed in 11sSMC-positive patients and 10 patients were positive for SRY and one was negative. Among the 10 SRY-positive patients, two cases had hirsutism and clitoral enlargement and two cases had clitoral enlargement only. Nine sSMC and SRY-positive patients underwent gonadectomy and one had left gonadal gonadoblastoma with seminoma and right gonadal seminoma .

Conclusions: Although the sSMC positive detection rate in DSD patients is uncommon (5.33% in our sample), the positive SRY detection rate in sSMC-positive TS patients was extremely high in our TS patients. And TS patients with sSMC and SRY positive had a significantly increased risk of gonadal germ cell tumors. Routine SRY screening should be performed in TS patients with sSMC, and a gonadectomy should be performed in TS patients with sSMC and SRY positive to prevent the occurrence of tumors.